Sofa



FIG. 1 is a front elevational view of a sofa showing my new design;

FIG. 2 is a front perspective view; and,

FIG. 3 is a right side elevational view, the left side being a mirror image thereof.

The undisclosed rear and bottom surfaces of the sofa are conventionally plain and unornamented. 

The ornamental design for a sofa, as shown and described. 